MP-376 (Aeroquin) for chronicPseudomonas aeruginosainfections

Drivers of absolute systemic bioavailability after oral pulmonary inhalation in humans

There are few studies in humans dealing with the relationship between physico-chemical properties of drugs and their systemic bioavailability after administration via oral inhalation route (Fpulm). Getting further insight in the determinants of Fpulm after oral pulmonary inhalation could be of value for drugs considered for a systemic delivery as a result of poor oral bioavailability, as well as for drugs considered for a local delivery to anticipate their undesirable systemic effects. To better delineate the parameters influencing the systemic delivery after oral pulmonary inhalation in humans, we studied the influence of physico-chemical and permeability properties obtained in silico on the rate and extent of Fpulm in a series of 77 compounds with or without marketing approval for pulmonary delivery, and intended either for local or for systemic delivery. Principal component analysis (PCA) showed mainly that Fpulm was positively correlated with Papp and negatively correlated with %TPSA, without a significant influence of solubility and ionization fraction, and no apparent link with lipophilicity and drug size parameters. As a result of the small sample set, the performance of the different models as predictive of Fpulm were quite average with random forest algorithm displaying the best performance. As a whole, the different models captured between 50 and 60% of the variability with a prediction error of less than 20%. Tmax data suggested a significant positive influence of lipophilicity on absorption rate while charge apparently had no influence. A significant linear relationship between Cmax and dose (R² = "0.79) highlighted that Cmax was primarily dependent on dose and absorption rate and could be used to estimate Cmax in humans for new inhaled drugs.

Antimicrobial molecules in the lung: formulation challenges and future directions for innovation

Inhaled antimicrobials have been extremely beneficial in treating respiratory infections, particularly chronic infections in a lung with cystic fibrosis. The pulmonary delivery of antibiotics has been demonstrated to improve treatment efficacy, reduce systemic side effects and, critically, reduce drug exposure to commensal bacteria compared with systemic administration, reducing selective pressure for antimicrobial resistance. This review will explore the specific challenges of pulmonary delivery of a number of differing antimicrobial molecules, and the formulation and technological approaches that have been used to overcome these difficulties. It will also explore the future challenges being faced in the development of inhaled products and respiratory infection treatment, and identify future directions of innovation, with a particular focus on respiratory infections caused by multiple drug-resistant pathogens.

Effectiveness of treatment with nebulized colistin in patients with COPD

Objectives

To analyze whether the introduction of nebulized colistin in patients with chronic obstructive pulmonary disease (COPD) and infection with Pseudomonas aeruginosa (PA) is associated with a decrease of the number and duration of severe exacerbations.

Materials and methods

Thirty six patients with COPD and infection with PA treated with nebulized colistin attending a day hospital during a 5-year (January 2010–December 2014) period were prospectively included. Repeated-measures t-tests were used to assess whether the introduction of colistin was associated with changes in the number of exacerbations or the length of the hospitalizations, comparing for each patient the year prior to the introduction of colistin with the year after.

Results

After the introduction of colistin, the number of admissions decreased from 2.0 to 0.9 per individual year (P=0.0007), and hospitalizations were shorter (23.3 vs 10.9 days, P=0.00005). These results persisted when patients with and without bronchiectasis or with and without persistence of Pseudomonas were separately analyzed. No pre–post differences were detected in the number of exacerbations not requiring admission.

Conclusion

Nebulized colistin seems associated with a strong decrease in the number and duration of hospitalizations due to exacerbation in patients with COPD and infection with PA. Clinical trials with a larger number of patients are needed in order to confirm these results.

Levofloxacin inhalation solution for the treatment of chronic Pseudomonas aeruginosa infection among patients with cystic fibrosis

Chronic pulmonary infections are common among patients with cystic fibrosis. By 10 years of age, Pseudomonas aeruginosa is the predominant pathogen. Inhaled levofloxacin solution (MP-376) is a promising new therapy that exhibits rapid antibacterial activity and excellent biofilm penetration against P. aeruginosa. In the largest trial to date, 151 patients were randomized to receive MP-376 or placebo. At the end of the 28-day treatment period, patients who received MP-376 had decreased P. aeruginosa density in sputum, improved lung function parameters and improved respiratory symptoms. MP-376 also appeared to be safe and well tolerated. The results of two recently completed Phase III trials have not yet been released; however, these data will be critical in determining whether MP-376 is a safe and effective maintenance therapy for chronic pulmonary P. aeruginosa infections among patients with cystic fibrosis.

Inhaled antibiotics to treat lung infection

The development of inhaled antibiotics to treat lung infection is an active field, with four approved products in the USA and more in the late stages of clinical development. The efficacies of TOBI® tobramycin (Novartis) and Cayston® aztreonam lysate (Gilead), the approved inhaled antibiotics for cystic fibrosis (CF) patients colonized with Pseudomonas aeruginosa, have been well documented. Recent approvals for a second-generation tobramycin solution, Bethkis®, and a tobramycin powder formulation in a dry-powder inhaler (DPI), TOBI Podhaler®, indicate that the inhaled antibiotic marketplace in CF is becoming very competitive. Other indications are also receiving interest. While there have been a number of recent reviews from a clinical, technical or regulatory perspective in the field of inhaled antibiotics, as well as others focused on a specific product or data from a recent clinical trial, there have not been any that describe the patent coverage of these products. This review addresses that missing piece.

Antibiotics for treatment and prevention of exacerbations of chronic obstructive pulmonary disease

Acute exacerbations (AE) can be recurrent problems for patients with moderate-to-severe chronic obstructive pulmonary disease (COPD) increasing morbidity and mortality. Evidence suggests that ≥50% of acute exacerbations involve bacteria requiring treatment with an antibiotic which should have high activity against the causative pathogens. However, sputum analysis is not a pre-requisite for antibiotic prescription in outpatients as results are delayed and patients are likely to be colonised with bacteria in the stable state. Clinicians rely on the clinical symptoms, sputum appearance and the patient's medical history to decide if an AE-COPD should be treated with antibiotics. This article reviews the available data of antibiotic trials in AE-COPD. Management of frequent exacerbators is particularly challenging for physicians. This may include antibiotic prophylaxis, especially macrolides because of anti-inflammatory properties; though successful in reducing exacerbations, concerns about resistance development remain. Inhalation of antibiotics achieves high local concentrations and minimal systemic exposure; therefore, it may represent an attractive alternative for antibiotic prophylaxis in certain COPD patients. Inhaled antibiotic prophylaxis has been successfully used in other respiratory conditions such as non-cystic fibrosis bronchiectasis which itself might be present in COPD patients who have chronic bacterial infection, particularly with Pseudomonas aeruginosa.